A hybrid fault location method for overhead lines combined with underground cables using DWT and SVM

This paper presents a single-ended and hybrid traveling wave based fault location method for power transmission systems where overhead lines are combined with underground cables. In the proposed hybrid method, Discrete Wavelet Transform (DWT) is utilized to extract transient information of recorded voltages and support vector machines (SVM) are used to identify the section of the fault. The normalized wavelet energies of post-fault voltages are used as the input to the classifier. Bewley diagrams are observed for the traveling wave pattern in the overhead line and underground cable to locate the fault. The transient voltages for different types of faults and locations along the overhead line section as well as the underground cable section are obtained through ATP simulations. MATLAB is used to process the simulated transients and apply the proposed method. The performance of the method is tested on various scenarios.